A ski lift damaged in Monday morning's avalanche on the Turoa side of Mount Ruapehu could be out of action for months.

The avalanche was triggered about 8.30am by a routine control check by Ruapehu Alpine Lifts, which manages the ski-field.

Its chief executive Ross Copland says the avalanche struck the top of the High Noon Express chairlift - one of eight chairlifts at the ski field.

He says it would be inoperable for at least one week.

If the haul rope was found to be damaged, however, a new rope might need to be imported from Europe which could take months.

No one was injured in the avalanche and all staff were accounted for.